Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain.
Philos Trans R Soc Lond B Biol Sci. 2021 Sep 13;376(1833):20200104. doi: 10.1098/rstb.2020.0104. Epub 2021 Jul 26.
Hybrids provide an interesting model to study the evolution of sex-determining genes and sex chromosome systems as they offer the opportunity to see how independently evolving sex-determining pathways interact . In this context, the genus represents a stimulating model, since species with non-homologous sex chromosomes and different sex-determining genes have been identified. In addition, the possibility of interspecies breeding is favoured in this group, which arose by alloploidization events, with species ploidy ranging from 2 = 2 = 20 in (the only diploid representative of the genus) to 2 = 12 = 108 in . To study how two sex-determining genes interact , × s hybrids were produced. Gonadal differentiation in these hybrids revealed that the gene is dominant over male-determining sex chromosomes (Y or Z), even though the Y chromosome is dominant in (Y > W>Z). In the absence of the gene (the Z chromosome from is present), the W chromosome from is able to trigger ovarian development. Testicular differentiation will take place in the absence of W chromosomes from any of the parental species. The dominance/recessivity relationships between these sex-determining loci in the context of either parental genome remains unknown. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)'.
杂种提供了一个有趣的模型来研究性别决定基因和性染色体系统的进化，因为它们提供了观察独立进化的性别决定途径如何相互作用的机会。在这种情况下，代表了一个刺激的模型，因为已经确定了具有非同源性染色体和不同性别决定基因的物种。此外，在这个由异源多倍体事件引起的群体中，种间杂交的可能性得到了促进，物种的倍性范围从 2 = 2 = 20 的（该属唯一的二倍体代表）到 2 = 12 = 108 的。为了研究两个性别决定基因如何相互作用，产生了 × s 杂种。这些杂种的性腺分化表明，基因在雄性决定性别染色体（Y 或 Z）上是显性的，尽管 Y 染色体在 （Y > W>Z）中是显性的。在没有基因的情况下（来自 的 Z 染色体存在），来自 的 W 染色体能够触发卵巢发育。在任何亲本物种的 W 染色体缺失的情况下，睾丸将发生分化。这些性别决定基因座在任一亲本基因组背景下的显性/隐性关系尚不清楚。本文是主题问题“挑战性染色体进化的范例：以脊椎动物为重点的实证和理论见解（第二部分）”的一部分。
